title: Analysis of telomere dynamics in peripheral blood cells from patients with Lynch syndrome.
abstract: BACKGROUND
  In patients with Lynch syndrome, germline mutations in DNA mismatch repair (MMR) genes cause a high risk of developing a broad spectrum of cancers. To date, the management of patients with Lynch syndrome has represented a major challenge because of large variations in age at cancer onset. Several factors, including genetic anticipation, have been proposed to explain this phenotypic heterogeneity, but the molecular mechanisms remain unknown. Telomere shortening is a common event in tumorigenesis and also has been observed in different familial cancers. In this study, the authors investigated the possibility of a relation between telomere length and cancer onset in patients with Lynch syndrome.
  
  
  METHODS
  The mean telomere length was measured using quantitative polymerase chain reaction in peripheral blood samples from a control group of 50 individuals, from 31 unaffected mutation carriers, and from 43 affected patients, and the results were correlated with both gene mutation and cancer occurrence. In affected patients, telomere attrition was correlated with age at cancer onset. In all patients, a t test was used to assess the linearity of the regression.
  
  
  RESULTS
  A significant correlation between telomere length and age was observed in both affected and unaffected mutation carriers (P = .0016 and P = .004, respectively) and in mutS homolog 2 (MSH2) mutation carriers (P = .0002) but not in mutL homolog 1 (MLH1) mutation carriers. Telomere attrition was correlated significantly with age at onset in MSH2 carriers (P = .004), whereas an opposite trend toward longer telomeres in patients with delayed onset was observed in MLH1 carriers.
  
  
  CONCLUSIONS
  The current data suggested that telomere dynamics differ between MLH1 and MSH2 mutation carriers. It is possible that subtle, gene-specific mechanisms can be linked to cancer onset and anticipation in patients with Lynch syndrome.
authors.affiliation: Medical Genetics Unit, Department of Biomedicine in Childhood, "Aldo Moro" University of Bari, Bari, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Bozzao
authors.forename: Patrizia
authors.initials: P
authors.lastname: Lastella
authors.forename: Maurizio
authors.initials: M
authors.lastname: Ponz de Leon
authors.forename: Monica
authors.initials: M
authors.lastname: Pedroni
authors.forename: Carmela
authors.initials: C
authors.lastname: Di Gregorio
authors.forename: Francesco D
authors.initials: FD
authors.lastname: D'Ovidio
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Resta
authors.forename: Fernando
authors.initials: F
authors.lastname: Prete
authors.forename: Ginevra
authors.initials: G
authors.lastname: Guanti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Stella
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D000328:Adult; D017668:Age of Onset; D000368:Aged; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000097:blood / Q000235:genetics*; D053843:DNA Mismatch Repair / Q000235:genetics*; D005260:Female; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000235:genetics*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics*; D010375:Pedigree; D016615:Telomere / Q000473:pathology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein